Hull blisters. Repair or leave alone?

[Terra Nova]

Originally Posted by Jcolman

...I may take my dremel tool and sand down a few of the larger blisters and fill them next week just to get a feel for the job...

I love my Dremel. But if you take a mini grinder along, instead, you could open all the major blisters in the time you took to explore a few. Then, after letting them all dry out, return to do the matting, filling and fairing.

[Jcolman]

Originally Posted by Terra Nova

I love my Dremel. But if you take a mini grinder along, instead, you could open all the major blisters in the time you took to explore a few. Then, after letting them all dry out, return to do the matting, filling and fairing.

I thought that all one needed to do was to fill in the blister (after grinding it out) with epoxy then fair it out?

[model 10]

Originally Posted by Jcolman

I thought that all one needed to do was to fill in the blister (after grinding it out) with epoxy then fair it out?

I think they are talking about mondo blisters. For the most part, the way you see it is the norm.

[Terra Nova]

Look at it this way--every time you haulout, you grind another batch of major blisters; they were only minor blisters when you last hauled out. If you only putty the blister holes, eventually your hull will be mostly putty holding a bunch of blisters together.

[minaret]

Originally Posted by Jcolman

I thought that all one needed to do was to fill in the blister (after grinding it out) with epoxy then fair it out?

Absolutely not. Many amateurs will tell you this is OK, but it's not. Glass those blisters back up. And make sure your hull is actually dry before you do so.

[Jcolman]

Originally Posted by minaret

Absolutely not. Many amateurs will tell you this is OK, but it's not. Glass those blisters back up. And make sure your hull is actually dry before you do so.

My boat has been out of the water for about a month. It's scheduled to be splashed again in June. Is a month long enough for the hull to dry out? The old paint is still on the hull.

[Terra Nova]

It would have been better if you had been letting your blisters dry out all that time.

[minaret]

Originally Posted by Jcolman

My boat has been out of the water for about a month. It's scheduled to be splashed again in June. Is a month long enough for the hull to dry out? The old paint is still on the hull.

No. It won't have been drying at all with the paint on. It has to be peeled to bare glass for that. I've seen boats take a year to air dry. After peeling. And 2" blisters means a substantial saturation problem.

[oldragbaggers]

The professionals we watched do blister repair in southern California peeled the hull, then tented it and applied heat lamps until the moisture level was low enough to do the work.

As far as the matting, when we did the blisters on our Newport we chopped mat into the epoxy mixture and filled the holes with that. I don't know if that would be acceptable practice these days. This was in 1986 and that was the standard practice used at boatyards back then.

[Jcolman]

Originally Posted by minaret

No. It won't have been drying at all with the paint on. It has to be peeled to bare glass for that. I've seen boats take a year to air dry. After peeling. And 2" blisters means a substantial saturation problem.

Ok thanks. I think I'm just going to put the boat back in the water for now and pull it out next fall and see if I can dry it out over the winter.

[minaret]

Originally Posted by Jcolman

Ok thanks. I think I'm just going to put the boat back in the water for now and pull it out next fall and see if I can dry it out over the winter.

Good call. It won't get that much worse in just one more season, and a proper fix will take time.

[Adodero]

We were faced with a similar issue recently with our new boat and had resolved to peel and dry, only we got lucky and all the blisters came off with the bottom paint. No one sanded the hull prior to paint application and the paint blistered, the gelcoat was fine except in a few small areas.

We had resolved to do what you decided to do enjoy the boat until fall, haul in the fall, peel, then let it dry out and re-apply when the hull is dry. In FL, it doesn't really matter when you do it, because it's pretty humid year round, but in areas further north, the hull will dry faster in the fall and winter months, especially as humid as it gets where you are in summer. I would ask someone locally about tenting, though, everyone I asked down here said it made no difference (but that may differ depending on where you are). The folks we talked to seemed to indicate 4-6 months was average.

To give you an idea on price, we were quoted $115/ft for someone to peel, powerwash once every two weeks, monitor the hull moisture level, apply the barrier coat, and bottom paint. I was quoted $700 for just the peeling, if you don't mind doing the work yourself (it needs to be powerwashed regularly).

[Suijin]

I suggest in the fall you have the bottom media blasted or have all the paint removed in some fashion. The boat is new to you and you don't know what's going on under the paint, so best to get it all off so you can get a good view of the whole hull and so better decide what needs to be done. Let her sit and dry out as much as she will over the winter and in the spring can reassess where you stand. She may not need to be peeled...that's a potentially drastic and extremely expensive measure when you don't even know her true state.

You haven't said how many blisters we're talking about. Five? Twenty? More? Anything more than five the first thing I would do is go out and buy a real grinder, which will take about 1 minute to deal with each blister instead of buzzing away with a Dremel. While you might not enjoy doing this kind of work, it's not hard and you can do it at a fraction of the cost of what the yard will charge you.

[Jcolman]

Originally Posted by Suijin

I suggest in the fall you have the bottom media blasted or have all the paint removed in some fashion. The boat is new to you and you don't know what's going on under the paint, so best to get it all off so you can get a good view of the whole hull and so better decide what needs to be done. Let her sit and dry out as much as she will over the winter and in the spring can reassess where you stand. She may not need to be peeled...that's a potentially drastic and extremely expensive measure when you don't even know her true state.

You haven't said how many blisters we're talking about. Five? Twenty? More? Anything more than five the first thing I would do is go out and buy a real grinder, which will take about 1 minute to deal with each blister instead of buzzing away with a Dremel. While you might not enjoy doing this kind of work, it's not hard and you can do it at a fraction of the cost of what the yard will charge you.

I think there's about 5 or 6 large blisters and maybe 15-20 smaller ones. I need to do a count next time I'm on the boat. The larger ones look like a sea shell, smooth to the touch on the inside, maybe 1/4" or less deep.

I don't mind spending the money on a grinder. I just need to find someone at the yard to show me how to do the job right and I'll do the work myself.

[oldragbaggers]

If you're only talking about 25 or so blisters it's not a big deal. We did several hundred in a week. Since the problem isn't that severe I agree with those who suggested you wait until fall. Strip off your paint, either by soda blasting, or we have used an environmentally friendly stripper called Marine Soy Strip. It works pretty well. Grind out the blisters you have and then let it dry over the winter. Honestly, fixing that many blisters is a day of filling and a day of sanding.